1. Field of the Invention
The present general inventive concept generally relates to a memory controller, and more particularly, to a memory controller to use a bad block, devices including the same, and an operating method of the memory controller.
2. Description of the Related Art
Memory devices are largely divided into volatile memory devices and non-volatile memory devices.
Volatile memory devices have fast read and write speed but lose data stored therein when they are not powered. On the contrary, non-volatile memory devices retain data stored therein even when they are not powered. Accordingly, non-volatile memory devices are used to store data that needs to be retained regardless of the supply of power.
Examples of non-volatile memory devices are mask read-only memory (MROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM).
In general, MROM, PROM, and EPROM do not allow data to be erased or written freely, and therefore, it is not easy to update data stored in MROM, PROM, and EPROM. Contrarily, EEPROM allows data to be electrically erased and written, and therefore, the application of EEPROM has been expanded for system programming requiring continuous update or for auxiliary memory. In particular, flash EEPROM has higher integration than EEPROM and is thus very advantageous in that it is used as large-capacity auxiliary memory.
Among flash EEPROM, NAND flash memory has much higher integration than NOR flash memory.
Non-volatile memory devices include a plurality of memory cells. Each of the memory cells stores one or more bits. There has been a trend toward high integration, large capacity, and high performance of non-volatile memory devices with the increase of chip size. However, this trend accompanies the decrease in the circuit line width, the increase of the number of processes, and the increase of complexity with respect to non-volatile memory devices. These conditions lead the reduction of yield of chips. To overcome this problem, non-volatile memory devices include a redundant memory cell for replacing a defective memory cell.
In addition, non-volatile memory devices also include means for translating an address of a defective cell into an address of a redundant memory cell. When a bad block including a defective cell is detected during a test operation, the bad block is replaced by a redundant block.
As the bad block is replaced by the redundant block, a non-volatile memory device including the bad block can be released as a fair-quality product. However, since the number of redundant blocks included in a single non-volatile memory device is limited, it may happen that the number of bad blocks that have been detected exceeds the number of redundant blocks.